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Chapter 6. Materials Around Us

Chapter 6. Materials Around Us

Everything around us is made of one or more materials. The objects we use every day, such as books, tables, bottles, utensils, clothes, toys, and vehicles, are made from different materials according to their properties. Understanding the characteristics of materials helps us choose the right material for a particular purpose. This chapter introduces the concept of materials, their classification, physical properties, and the basic idea of matter.

CBSE Notes - Key Points

The following notes provide important definitions, scientific terms, key concepts, and revision points from the chapter. These notes are useful for quick revision before school examinations and CBSE assessments.

Important Keywords

• Material
• Matter
• Classification
• Lustre
• Lustrous Material
• Non-Lustrous Material
• Hard Material
• Soft Material
• Transparent Material
• Translucent Material
• Opaque Material
• Soluble Substance
• Insoluble Substance
• Mass
• Volume
• Kilogram (kg)
• Gram (g)
• Litre (L)
• Millilitre (mL)
• Physical Properties

Important Definitions

Material: A material is any substance that is used to make an object.

Matter: Anything that has mass and occupies space is called matter.

Classification: The process of grouping materials according to their similar properties.

Lustre: The shiny appearance of a material is called lustre.

Hard Material: A material that cannot be scratched or compressed easily.

Soft Material: A material that can be scratched or compressed easily.

Transparent Material: A material that allows almost all light to pass through it.

Translucent Material: A material that allows only some light to pass through it.

Opaque Material: A material that does not allow light to pass through it.

Soluble Substance: A substance that dissolves completely in water.

Insoluble Substance: A substance that does not dissolve in water.

Mass: The quantity of matter present in an object.

Volume: The space occupied by an object.

Scientific Terms

Scientific Term	Description
Material	A substance used for making objects.
Matter	Anything that has mass and occupies space.
Lustre	Shiny appearance of a material.
Mass	Amount of matter present in an object.
Volume	Space occupied by an object.
Transparent	Allows light to pass completely.
Translucent	Allows only partial light to pass.
Opaque	Does not allow light to pass.
Solubility	Ability of a substance to dissolve in water.

Important Facts

• Everything around us is made of matter.
• An object may be made from one or more materials.
• Materials are selected according to their properties.
• Classification makes the study of materials simple and systematic.
• Metals are generally lustrous.
• Wood, paper and rubber are usually non-lustrous.
• Stone and iron are hard materials.
• Sponge and cotton are soft materials.
• Glass, air and clean water are transparent.
• Butter paper and frosted glass are translucent.
• Wood, brick and metals are opaque.
• Sugar and salt are soluble in water.
• Sand, chalk powder and sawdust are insoluble in water.
• Mass is measured in kilograms and grams.
• Volume of liquids is measured in litres and millilitres.
• Every material occupies space.
• Every material has mass.
• The properties of materials determine their uses.

Examples of Material Properties

Property	Example
Lustrous	Gold, Copper
Non-Lustrous	Wood, Paper
Hard	Stone, Iron
Soft	Cotton, Sponge
Transparent	Glass, Water
Translucent	Butter Paper
Opaque	Wood, Brick
Soluble	Sugar, Salt
Insoluble	Sand, Chalk Powder

Quick Revision

• Everything around us is made of matter.
• Materials are chosen according to their properties.
• Objects may be made from one or more materials.
• Classification makes the study of materials easier.
• Lustrous materials have a shiny surface.
• Hard materials resist scratching.
• Soft materials are easily compressed.
• Transparent materials allow light to pass through.
• Translucent materials allow only partial light.
• Opaque materials block light completely.
• Sugar and salt dissolve in water.
• Sand and chalk powder do not dissolve in water.
• Mass is measured in kilograms.
• Volume is the space occupied by matter.
• Every material has both mass and volume.

Chapter 6. Materials Around Us

Chapter 6. Materials Around Us

Everything we use in our daily life is made of one or more materials. A material is the substance from which an object is made. Different materials possess different properties, and these properties determine their suitability for specific purposes. This chapter explains how materials are classified based on their physical properties such as appearance, hardness, transparency, solubility, mass, and volume. It also introduces the concept of matter and its importance in everyday life.

CBSE Full Notes

Introduction to Materials

Look around your home, classroom, or playground. You will find a variety of objects such as chairs, tables, books, bottles, toys, clothes, utensils, and electronic gadgets. Although these objects have different shapes, sizes, and uses, they are all made from different kinds of materials.

A single object may be made from one material or from several different materials. For example, a steel spoon is made from one material, whereas a school bag may contain cloth, plastic, metal, and rubber.

What is a Material?

A material is any substance that is used for making an object. The choice of material depends on the purpose for which the object is made. Different materials have different physical properties that make them useful for different applications.

Examples

• Wood is used for furniture.
• Glass is used for windows.
• Plastic is used for bottles and containers.
• Cotton is used for clothes.
• Iron is used for machines and tools.

Classification of Materials

Thousands of materials are available around us. Studying each material separately is difficult. Therefore, materials are grouped according to their common properties. This process is called classification of materials.

Advantages of Classification

• Makes the study of materials simple.
• Helps compare different materials.
• Makes identification easier.
• Helps select suitable materials for different purposes.
• Supports scientific research and industrial production.

Properties of Materials

Materials differ from one another because of their physical properties.

1. Appearance (Lustre)

Some materials have a shiny surface known as lustre. Such materials are called lustrous materials. Most metals are lustrous.

Examples of Lustrous Materials

• Gold
• Silver
• Copper
• Aluminium
• Iron

Materials that do not have a shiny surface are called non-lustrous materials.

Examples

• Wood
• Paper
• Rubber
• Cotton

2. Hardness

Hardness is the property that tells us whether a material can be scratched, cut, or compressed easily.

Hard Materials

• Stone
• Iron
• Steel
• Glass

Soft Materials

• Sponge
• Cotton
• Rubber
• Clay

3. Transparency

Materials are also classified according to the amount of light they allow to pass through them.

Transparent Materials

• Glass
• Clean Water
• Air

These materials allow almost all the light to pass through them, making objects visible clearly.

Translucent Materials

• Butter Paper
• Frosted Glass
• Thin Plastic Sheet

These materials allow only some light to pass through them, so objects appear blurred.

Opaque Materials

• Wood
• Brick
• Metal Sheet
• Cardboard

Opaque materials do not allow light to pass through them.

4. Solubility in Water

Some substances dissolve completely in water, whereas others do not.

Soluble Substances

• Sugar
• Salt
• Glucose

Insoluble Substances

• Sand
• Chalk Powder
• Sawdust
• Stone Dust

The property of dissolving in water is known as solubility.

5. Mass

Every material has mass. Mass is the amount of matter contained in an object. It tells us how heavy or light an object is.

SI Unit of Mass

• Kilogram (kg)
• Gram (g)

6. Volume

Every material occupies space. The amount of space occupied by a material is called its volume.

Units of Volume

• Litre (L)
• Millilitre (mL)

Matter

Anything that has mass and occupies space is called matter. Every object around us, whether solid, liquid, or gas, is made of matter.

Examples of Matter

• Air
• Water
• Stone
• Wood
• Plastic
• Iron

Importance of Material Properties

The properties of materials help us decide where and how they should be used.

Property	Application
Transparency	Windows and spectacles
Hardness	Construction materials and tools
Lustre	Jewellery and decorative items
Waterproof Nature	Raincoats and umbrellas
Solubility	Medicines and food preparation

Applications in Daily Life

• Manufacturing household utensils.
• Making furniture.
• Preparing medicines.
• Building houses and bridges.
• Producing sports equipment.
• Making transparent windows.
• Preparing food and beverages.
• Making waterproof products.

Remember These Points

• Every object is made from one or more materials.
• Materials are selected according to their properties.
• Classification helps us study materials systematically.
• Metals are generally lustrous.
• Stone and iron are hard materials.
• Sponge and cotton are soft materials.
• Glass and water are transparent materials.
• Butter paper is translucent.
• Wood and metals are opaque materials.
• Sugar and salt dissolve in water.
• Sand and chalk powder do not dissolve in water.
• Mass is measured in kilograms and grams.
• Volume is measured in litres and millilitres.
• Everything that has mass and occupies space is called matter.
• The properties of materials determine their everyday uses.

Chapter 6. Materials Around Us

Chapter 6. Materials Around Us

This assignment is based on the concepts covered in the chapter Materials Around Us. It includes objective, subjective, competency-based, case study, and Higher Order Thinking Skills (HOTS) questions prepared according to the latest CBSE pattern. Students should attempt all questions independently to strengthen their understanding and improve analytical skills.

Assignments - What Have You Learned?

Attempt all the following questions without referring to the textbook. These questions will help you revise the complete chapter and prepare effectively for examinations.

Test Your Learning

Fill in the Blanks

1. Every object around us is made of one or more __________.
2. The process of grouping materials based on their properties is called __________.
3. Materials having a shiny surface are called __________ materials.
4. Glass is a __________ material.
5. Wood is an __________ material.
6. Sugar is __________ in water.
7. Sand is __________ in water.
8. The SI unit of mass is __________.
9. The space occupied by a material is called __________.
10. Anything that has mass and occupies space is called __________.

True or False

1. All objects are made from only one material.
2. Metals are generally lustrous.
3. Butter paper is a transparent material.
4. Wood is an opaque material.
5. Salt dissolves completely in water.
6. Sponge is a hard material.
7. Every material has mass.
8. Volume is the amount of matter present in an object.
9. Classification helps us study materials more easily.
10. Air is a form of matter.

Match the Following

Column A	Column B
Lustrous Material	Gold
Transparent Material	Glass
Opaque Material	Wood
Soluble Substance	Sugar
SI Unit of Mass	Kilogram

One Word Answer

1. A substance used to make an object.
2. The shiny appearance of a material.
3. A material through which light passes completely.
4. A substance that dissolves in water.
5. The amount of matter present in an object.
6. The space occupied by an object.
7. The SI unit of mass.
8. Anything having mass and occupying space.
9. A hard, lustrous metal commonly used in utensils.
10. The process of grouping similar materials.

Very Short Answer Questions

1. What is a material?
2. What is matter?
3. Define lustre.
4. What are hard materials?
5. What are soft materials?
6. Define transparent material.
7. What is a soluble substance?
8. What is mass?
9. What is volume?
10. Why do we classify materials?

Short Answer Questions

1. Differentiate between lustrous and non-lustrous materials with examples.
2. Differentiate between hard and soft materials.
3. Differentiate between transparent, translucent, and opaque materials.
4. Explain soluble and insoluble substances with suitable examples.
5. Why is classification of materials important?
6. Explain the concept of matter.
7. Differentiate between mass and volume.
8. Why are different materials used for making different objects?
9. Explain any four properties of materials.
10. Write any four applications of different material properties in daily life.

Long Answer Questions

1. Explain the different properties of materials with suitable examples.
2. Describe the classification of materials and explain why it is important.
3. Explain the concepts of matter, mass, and volume in detail.
4. Discuss the practical applications of material properties in daily life.
5. Explain how the properties of materials help scientists, engineers, and manufacturers select suitable materials for different purposes.

Case Study Based Questions

Case Study: During a science activity, Riya collected different objects such as a glass tumbler, a wooden block, a sponge, a steel spoon, sugar, and sand. She observed that some materials were shiny, some allowed light to pass through, some dissolved in water, while others did not.

1. Which object among these is transparent?
2. Which material is lustrous?
3. Which substance dissolves completely in water?
4. Which material is soft?
5. Why is it useful to classify these materials according to their properties?

Competency Based Questions

1. Observe ten objects available in your classroom and classify them as hard or soft.
2. Collect five household materials and classify them as transparent, translucent, or opaque.
3. Perform a simple activity to identify soluble and insoluble substances using water and record your observations.
4. Prepare a table showing different objects used at home and the materials from which they are made.
5. Identify five objects made from more than one material and explain why different materials are used.

HOTS Questions (Higher Order Thinking Skills)

1. Why is glass used for windows while wood is not? Explain using the properties of materials.
2. Imagine that all materials around you were transparent. What problems would people face in everyday life?
3. Why is it important for engineers to study the properties of materials before constructing buildings or machines?
4. A raincoat and a cotton shirt are used in different weather conditions. Explain why they are made of different materials.
5. Suppose scientists discover a new material that is transparent, very hard, lightweight, and waterproof. Suggest five possible applications of this material in daily life.

Chapter 6. Materials Around Us

Chapter 7. Temperature and its Measurement

These CBSE Key Points are prepared according to the latest NCERT Curiosity textbook and CBSE competency-based pattern. They provide quick revision of important concepts, scientific terms, facts, and formulae that are frequently asked in school examinations.

CBSE Notes – Key Points

This section highlights the most important concepts of the chapter in an easy-to-revise format. Students should go through these points before examinations to strengthen their conceptual understanding and improve retention.

What is Temperature?

Temperature is the measure of the degree of hotness or coldness of a body. It helps us compare how hot or cold one object is with another. Temperature is measured using a thermometer and is expressed in different temperature scales.

Important Keywords

The following scientific terms are frequently used in this chapter and should be remembered for examinations.

Keyword	Meaning
Temperature	Measure of the hotness or coldness of a body.
Thermometer	An instrument used to measure temperature.
Clinical Thermometer	A thermometer used to measure human body temperature.
Laboratory Thermometer	A thermometer used for scientific experiments.
Celsius Scale	Commonly used temperature scale represented by °C.
Fahrenheit Scale	Temperature scale represented by °F.
Kelvin Scale	SI temperature scale represented by K.
Infrared Thermometer	A non-contact thermometer that measures temperature from a distance.
Air Temperature	The temperature of the surrounding atmosphere.
Heat Sensor	An electronic device that detects temperature changes in digital thermometers.

Important Definitions

Learning the following definitions will help students answer one-mark and competency-based questions effectively.

Term	Definition
Temperature	The degree of hotness or coldness of a body.
Thermometer	An instrument used to measure temperature accurately.
Clinical Thermometer	A thermometer specially designed to measure human body temperature.
Laboratory Thermometer	A thermometer used to measure the temperature of liquids and other substances in laboratories.
Kelvin	The SI unit of temperature.

Types of Thermometers

Different thermometers are designed for different purposes. Students should know their uses and major differences.

Thermometer	Used For	Main Feature
Clinical Thermometer	Human body	Measures body temperature accurately.
Digital Clinical Thermometer	Human body	Electronic, safe and easy to read.
Laboratory Thermometer	Experiments	Measures a wide range of temperatures.
Room Thermometer	Indoor air	Measures surrounding air temperature.
Infrared Thermometer	Body without contact	Measures temperature from a distance.

Temperature Scales

Scientists use different temperature scales depending on the purpose of measurement.

Scale	Symbol	Common Use
Celsius	°C	Daily life and school science.
Fahrenheit	°F	Used in some countries.
Kelvin	K	Scientific research and SI unit.

Important Scientific Facts

Remember these facts carefully as they are frequently asked in objective and short-answer questions.

• Temperature tells us how hot or cold an object is.
• Our sense of touch cannot accurately judge temperature.
• A thermometer provides accurate temperature measurement.
• The average normal human body temperature is 37°C (98.6°F).
• The SI unit of temperature is kelvin (K).
• Digital thermometers use electronic heat sensors.
• Mercury thermometers are being replaced because mercury is poisonous.
• Clinical thermometers are used only for measuring body temperature.
• Laboratory thermometers measure temperatures of liquids and other substances.
• Air temperature changes with weather and seasons.

Clinical Thermometer vs Laboratory Thermometer

The following comparison helps students understand the differences between the two commonly used thermometers.

Clinical Thermometer	Laboratory Thermometer
Measures body temperature.	Measures temperature of liquids and materials.
Used by doctors and at home.	Used in laboratories.
Limited temperature range.	Wide temperature range.
Suitable for medical purposes.	Suitable for scientific experiments.

Precautions While Using a Clinical Thermometer

Following these precautions ensures safe and accurate measurement of body temperature.

• Read the instruction manual before use.
• Wash the thermometer tip before and after every use.
• Keep the display unit away from water.
• Do not hold the thermometer by its tip.
• Wait for the beep before reading the temperature.

Precautions While Using a Laboratory Thermometer

These precautions help in obtaining correct temperature readings during experiments.

• Handle the thermometer carefully.
• Keep it in a vertical position.
• Do not allow the bulb to touch the container.
• Read the temperature while the thermometer is immersed.
• Take the reading at eye level.

Applications of Temperature Measurement

Temperature measurement is used in many fields of science and everyday life.

• Diagnosing fever.
• Scientific laboratory experiments.
• Weather forecasting.
• Food storage and refrigeration.
• Industrial manufacturing.
• Agriculture.
• Medical research.
• Environmental monitoring.
• Cooking and baking.
• Renewable energy studies.

Quick Revision

Revise these important points before your examination.

• Temperature is the measure of hotness or coldness.
• Thermometers are used to measure temperature.
• Clinical thermometers measure body temperature.
• Laboratory thermometers are used in experiments.
• 37°C = 98.6°F.
• Kelvin (K) is the SI unit of temperature.
• Touch cannot accurately determine temperature.
• Digital thermometers are safer than mercury thermometers.
• Laboratory thermometers should be read while immersed in the liquid.
• Temperature plays an important role in healthcare, science, industries, and weather forecasting.